Stabilization of 1-chloro-3,3,3-trifluoropropene

ABSTRACT

The use of a C 3  to C 6  alkene compound including a sole double bond, for limiting or preventing the isomerization of trans-1-chloro-3,3,3-trifluoropropene to cis-1-chloro-3,3,3-trifluoropropene. Also, a composition including 1-chloro-3,3,3-trifluoropropene and a C 3  to C 6  alkene compound including a sole double bond, and also to various uses of this composition, such as a process for heating or cooling a fluid.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/073,108, filed on Mar. 17, 2016, which claims the benefit of FrenchApplication No. 1552222, filed on Mar. 18, 2015. The entire contents ofeach of U.S. application Ser. No. 15/073,108 and French Application No.1552222 are hereby incorporated herein by reference in their entirety.

FIELD OF THE INVENTION

The present invention relates to compounds which make it possible tostabilize 1-chloro-3,3,3-trifluoroproprene and more specifically tolimit or prevent isomerization of the trans form to the cis form. Theinvention also relates to the use of such stabilizers in heat-transferapplications.

TECHNICAL BACKGROUND

Trans-1-chloro-3,3,3-trifluoroproprene (HCFO-1233zdE) is a product witha low global warming potential (GWP). It has thermodynamic andthermophysical properties that are very favorable for use as aheat-transfer fluid in cooling, air-conditioning, electricity production(in particular by means of organic Rankine cycles) and high-temperatureheat pump applications.

HCFO-1233zdE has an instability which manifests itself especially atrelatively high temperature. This instability consists of anisomerization of a fraction of the initial feedstock resulting in theformation of cis-1-chloro-3,3,3-trifluoroproprene (HCFO-1233zdZ).

As it happens, HCFO-1233zdZ is a less volatile product thanHCFO-1233zdE. The boiling point is about 40° C. for the Z isomer, andabout 18.3° C. for the E isomer. This difference implies a change in thethermodynamic and thermophysical properties of the product infacilities, and a loss of performance level, when the isomerizationoccurs.

Document WO 2009/003165 describes the risks of degradation ofhydrofluoroolefins and hydrochlorofluoroolefins, and also stabilizersfor combating this degradation. These stabilizers comprise free radicalscavenger compounds, acid scavenger compounds, oxygen scavengercompounds and polymerization inhibitors. Mention is in particular madeof: 1,2-epoxybutane, glycidyl methyl ether, d-l-limonene oxide,1,2-epoxymethylpropane, nitromethane, alpha-methylstyrene, isoprene,phenol, hydroquinones and hydrazine.

Document U.S. Pat. No. 7,795,480 describes a process for producing2-chloro-3,3,3-trifluoropropene (HCFO-1233xf). A phenomenon ofpolymerization of the compound is mentioned (but not an isomerizationphenomenon). Proposed stabilizers are p-tap(4-tert-amylphenol),methoxyhydroquinone, 4-methoxyphenol, triethylamine, diisopropylamine,butylated hydroxyanisole and thymol.

Document U.S. Pat. No. 8,217,208 describes the phenomenon ofisomerization of HFO-1233zdE under the effect of temperature, but itdoes not teach stabilizers which make it possible to limit thisisomerization.

Document US 2012/0226081 describes the risks of degradation ofhydrochloroolefins and of hydrochloroalkanes, and proposes a set ofpossible stabilizers: alpha-methylstyrene, alpha-pineneoxide,beta-pineneoxide, 1,2-epoxybutane, 1,2-hexadecene oxide and oxygenscavenger compounds such as diethylhydroxylamine, hydroquinone,methylethylketooxime and p-methoxyphenol.

Document US 2015/0034523 describes the risks of degradation ofhydrochloroolefins and proposes two families of stabilizers, namelymorpholines or trialkyl phosphates.

Virtually all of the stabilizers proposed in the prior art are solidproducts, or liquid products with a high boiling point. For example, theboiling point of alpha-methylstyrene is 165° C., the boiling point oflimonene oxide is greater than 200° C., etc.

Isoprene, mentioned in document WO 2009/003165, is for its part aproduct that is unstable in itself, and that must generally be combinedwith a compound such as 4-tert-butylpyrocatechol in order to prevent itfrom being polymerized.

The characteristics described above make the stabilizers unsuitable forcertain applications in which HCFO-1233zdE is liable to be used. This isin particular the case with applications using flooded evaporators (inparticular with compressors without lubricating oil). In suchapplications, the prior art stabilizers, with a high boiling point, areineffective since they concentrate in the evaporator and do not migratewith the heat-transfer fluid to the condenser.

There is therefore a need to provide stabilizers which make it possibleto limit or prevent the isomerization of HCFO-1233zdE to HCFO-1233zdZ,in particular in vapor compression systems such as air-conditioning,refrigeration, heat-pump and organic Rankine cycle systems, and quiteparticularly systems comprising a flooded evaporator.

SUMMARY OF THE INVENTION

The invention relates firstly to the use of a C₃ to C₆ alkene compoundcomprising a sole double bond, for limiting or preventing theisomerization of trans-1-chloro-3,3,3-trifluoropropene tocis-1-chloro-3,3,3-trifluoropropene.

According to one embodiment, the alkene compound is a butene or apentene.

According to one embodiment, the alkene compound has:

-   -   a boiling point less than or equal to 100° C., preferably less        than or equal to 75° C., and more particularly preferably less        than or equal to 50° C.; and/or    -   a solidification temperature less than or equal to 0° C.,        preferably less than or equal to −25° C., and more particularly        preferably less than or equal to −50° C.

According to one embodiment, the alkene compound is 2-methylbut-2-ene.

According to one embodiment, the alkene compound is 3-methylbut-1-ene.

A subject of the invention is also a composition comprising1-chloro-3,3,3-trifluoropropene and a C₃ to C₆ alkene compoundcomprising a sole double bond.

According to one embodiment, the alkene compound is a butene or apentene.

According to one embodiment, the alkene compound has:

-   -   a boiling point less than or equal to 100° C., preferably less        than or equal to 75° C., and more particularly preferably less        than or equal to 50° C.; and/or    -   a solidification temperature less than or equal to 0° C.,        preferably less than or equal to −25° C., and more particularly        preferably less than or equal to −50° C.

According to one embodiment, the alkene compound is 2-methylbut-2-ene.

According to one embodiment, the alkene compound is 3-methylbut-1-ene.

According to one embodiment, the compound comprises from 0.01% to 5%,preferably from 0.1% to 2% and more particularly from 0.2% to 1%, byweight, of alkene compound.

According to one embodiment, the 1-chloro-3,3,3-trifluoropropene is intrans form in a weight proportion greater than or equal to 90%,preferably greater than or equal to 95%, more particularly preferablygreater than or equal to 98%, even more particularly preferably greaterthan or equal to 99%, and ideally greater than or equal to 99.5%, oreven greater than 99.9%.

According to one embodiment, the composition also comprises one or moreheat-transfer compounds other than 1-chloro-3,3,3-trifluoropropeneand/or one or more additives chosen from stabilizers other than thealkene compound, lubricants, surfactants, tracers, fluorescent agents,odorous agents, solubilizing agents, and mixtures thereof.

A subject of the invention is also the use of the above composition as aheat-transfer fluid in a vapor compression system.

According to one embodiment, the vapor compression system is:

-   -   an air-conditioning system; or    -   a refrigeration system; or    -   a freezing system; or    -   a heat pump system.

According to one embodiment, the above use is a use as a heat-transferfluid in a thermal engine.

According to one embodiment, the heat-transfer fluid is at a temperaturegreater than or equal to 100° C., preferably greater than or equal to140° C., more particularly preferably greater than or equal to 180° C.,for at least one fraction of the duration of its use.

According to one embodiment, the heat-transfer fluid is evaporated in aflooded evaporator.

A subject of the invention is also a heat-transfer facility comprising acircuit containing the above composition as a heat-transfer fluid.

According to one embodiment, the facility is chosen from mobile orstationary facilities for heating via a heat pump, for air-conditioning,for refrigeration, or for freezing and thermal engines.

According to one embodiment, the facility comprises a floodedevaporator.

A subject of the invention is also a process for heating or cooling afluid or a body by means of a vapor compression system containing aheat-transfer fluid, said process comprising successively theevaporation of the heat-transfer fluid, the compression of theheat-transfer fluid, the condensation of the heat-transfer fluid and theexpansion of the heat-transfer fluid, in which the heat-transfer fluidis the composition described above.

A subject of the invention is also a process for producing electricityby means of a thermal engine, said process comprising successively theevaporation of the heat-transfer fluid, the expansion of theheat-transfer fluid in a turbine which makes it possible to generateelectricity, the condensation of the heat-transfer fluid and thecompression of the heat-transfer fluid, in which the heat-transfer fluidis the composition described above.

The present invention makes it possible to overcome the drawbacks of theprior art. It provides more particularly stabilizers which make itpossible to limit or prevent the isomerization of HCFO-1233zdE toHCFO-1233zdZ, in particular in vapor compression systems such asair-conditioning, refrigeration, heat pump and thermal engine systems,and quite particularly the systems comprising a flooded evaporator.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The invention is now described in greater detail and in a nonlimitingmanner in the description which follows.

Unless otherwise mentioned, throughout the application, the proportionsof compounds indicated are given as weight percentages.

The invention is based on the discovery that C₃ to C₆ alkene compoundscomprising a sole double bond make it possible to stabilizeHCFO-1233zdE, i.e. to limit or prevent the isomerization thereof toHCFO-1233zdZ, in particular at high temperatures.

The stabilizing compounds of the invention are therefore propene,butenes, pentenes and hexenes. Butenes and pentenes are preferred.Pentenes are even more particularly preferred.

The stabilizing compounds of the invention may comprise a linear orbranched chain and preferably a branched chain.

Preferably, they have a boiling point less than or equal to 100° C.,more preferably less than or equal to 75° C., and more particularlypreferably less than or equal to 50° C.

The term “boiling point” is intended to mean the boiling point at apressure of 101.325 kPa, as determined according to standard NF EN 378-1from April 2008.

Likewise preferably, they have a solidification temperature less than orequal to 0° C., preferably less than or equal to −25° C., and moreparticularly preferably less than or equal to −50° C.

The solidification temperature is determined according to Test No. 102:Melting point/Melting range (OECD guidelines for the testing ofchemicals, Section 1, OECD publications, Paris, 1995, available at theweb address http://dx.doi.org/10.1787/9789264069534-fr).

Stabilizing compounds of the invention are in particular:

-   -   but-1-ene;    -   cis-but-2-ene;    -   trans-but-2-ene;    -   2-methylprop-1-ene;    -   pent-1-ene;    -   cis-pent-2-ene;    -   trans-pent-2-ene;    -   2-methylbut-1-ene;    -   2-methylbut-2-ene; and    -   3-methylbut-1-ene.

Among the preferred compounds are in particular 2-methylbut-2-ene, offormula (CH₃)₂C═CH—CH₃ (boiling point of approximately 39° C.), and3-methylbut-1-ene, of formula CH₃—CH(CH₃)—CH═CH₂ (boiling point ofapproximately 25° C.).

Two or more than two of the above compounds may also be used incombination.

The stabilizing compounds according to the invention are thusadvantageously used in combination with HCFO-1233zd, and moreparticularly with HCFO-1233zdE, in heat-transfer applications.

Thus, the invention provides a composition, in particular of use forheat-transfer applications, comprising at least HCFO-1233zd and astabilizing compound described above.

The weight proportion of the stabilizing compounds above in thecomposition may in particular be: from 0.01% to 0.05%; or from 0.05% to0.1%; or from 0.1% to 0.2%; or from 0.2% to 0.3%; or from 0.3% to 0.4%;or from 0.4% to 0.5%; or from 0.5% to 0.6%; or from 0.6% to 0.7%; orfrom 0.7% to 0.8%; or from 0.8% to 0.9%; or from 0.9% to 1%; or from 1%to 1.2%; or from 1.2% to 1.5%; or from 1.5% to 2%; or from 2% to 3%; orfrom 3% to 4%; or from 4% to 5%.

The composition may comprise HCFO-1233zdE and optionally HCFO-1233zdZ.Advantageously, the proportion of HCFO-1233zdE, relative to the totalHCFO-1233zd, is greater than or equal to 90%, or greater than or equalto 91%, or greater than or equal to 92%, or greater than or equal to93%, or greater than or equal to 94%, or greater than or equal to 95%,or greater than or equal to 96%, or greater than or equal to 97%, orgreater than or equal to 98%, or greater than or equal to 99%, orgreater than or equal to 99.1%, or greater than or equal to 99.2%, orgreater than or equal to 99.3%, or greater than or equal to 99.4%, orgreater than or equal to 99.5%, or greater than or equal to 99.6%, orgreater than or equal to 99.7%, or greater than or equal to 99.8%, orgreater than or equal to 99.9%, or greater than or equal to 99.91%, orgreater than or equal to 99.92%, or greater than or equal to 99.93%, orgreater than or equal to 99.94%, or greater than or equal to 99.95%, orgreater than or equal to 99.96%, or greater than or equal to 99.97%, orgreater than or equal to 99.98%, or greater than or equal to 99.99%.

The presence of the stabilizing compound makes it possible to limit orprevent an increase in the proportion of HCFO-1233zdZ in the compositionover time and/or in the event of the application of relatively hightemperatures.

The composition of the invention may also comprise various additives.When it is a heat-transfer composition, the additives may in particularbe chosen from lubricants, nanoparticles, stabilizers (other than thestabilizing compounds of the invention), surfactants, tracers,fluorescent agents, odorous agents and solubilizing agents.

The stabilizer(s), when it (they) is (are) present, preferablyrepresent(s) at most 5% by weight in the heat-transfer composition.Among the stabilizers, mention may in particular be made ofnitromethane, ascorbic acid, terephthalic acid, azoles such astolutriazole or benzotriazole, phenolic compounds such as tocopherol,hydroquinone, t-butylhydroquinone, 2,6-di-tert-butyl-4-methylphenol,epoxides (alkyl optionally fluorinated or perfluorinated or alkenyl oraromatic) such as n-butyl glycidyl ether, hexanediol diglycidyl ether,allyl glycidyl ether, or butyl phenyl glycidyl ether, phosphites,phosphonates, thiols and lactones.

By way of lubricants, use may in particular be made of oils of mineralorigin, silicone oils, paraffins of natural origin, naphthenes,synthetic paraffins, alkylbenzenes, poly-alpha-olefins, polyalkeneglycols, polyol esters and/or polyvinyl ethers.

According to one advantageous embodiment of the invention, thecomposition of the invention is, however, free of lubricant.

By way of nanoparticles, use may in particular be made of carbonnanoparticles, metal (copper, aluminum) oxides, TiO₂, Al₂O₃, MoS₂, etc.

By way of tracers (capable of being detected), mention may be made ofdeuterated or non-deuterated hydrofluorocarbons, deuteratedhydrocarbons, perfluorocarbons, fluoroethers, brominated compounds,iodinated compounds, alcohols, aldehydes, ketones, nitrous oxide andcombinations thereof. The tracer is other than the heat-transfercompound(s) making up the heat-transfer fluid.

By way of solubilizing agents, mention may be made of hydrocarbons,dimethyl ether, polyoxyalkylene ethers, amides, ketones, nitriles,chlorocarbons, esters, lactones, aryl ethers, fluoroethers and1,1,1-trifluoroalkanes. The solubilizing agent is other than theheat-transfer compound(s) making up the heat-transfer fluid.

By way of fluorescent agents, mention may be made of naphthalimides,perylenes, coumarins, anthracenes, phenanthracenes, xanthenes,thioxanthenes, naphthoxanthenes, fluoresceins and derivatives andcombinations thereof.

By way of odorous agents, mention may be made of alkyl acrylates, allylacrylates, acrylic acids, acrylesters, alkyl ethers, alkyl esters,alkynes, aldehydes, thiols, thioethers, disulfides,allylisothiocyanates, alkanoic acids, amines, norbornenes, norbornenederivatives, cyclohexene, heterocyclic aromatic compounds, ascaridol,o-methoxy(methyl)phenol and combinations thereof.

The composition according to the invention may also comprise at leastone other heat-transfer compound, in addition to the HCFO-1233zd. Suchother optional heat-transfer compound may in particular be ahydrocarbon, ether, hydrofluoroether, hydrofluorocarbon,hydrochlorofluorocarbon, hydrofluoroolefin, hydrochloroolefin orhydrochlorofluoroolefin compound.

By way of example, said other heat-transfer compound may be chosen from1,1,1,4,4,4-hexafluorobut-2-ene (HFO-1336mmz, E or Z isomer),3,3,4,4,4-pentafluorobut-1-ene (HFO-1345fz),2,4,4,4-tetrafluorobut-1-ene (HFO-1354mfy), 1,1,1,3,3-pentafluoropropane(HFC-245fa), 2,3,3,3-tetrafluoropropene (HFO-1234yf),1,3,3,3-tetrafluoropropene (HFO-1234ze), difluoromethane (HFC-32),1,1,1,2-tetrafluoroethane (HFC-134a), 1,1,2,2-tetrafluoroethane(HFC-134), 1,1-difluoroethane (HFC-152a), pentafluoroethane (HFC-125),1,1,1,3,3-pentafluorobutane (HFC-365mfc), methoxynonafluorobutane(HFE7100), butane (HC-600), 2-methylbutane (HC-601a), pentane (HC-601),ethyl ether, methyl acetate and combinations thereof.

In the composition of the invention, the HCFO-1233zd may represent inparticular from 1% to 5% of the composition; or from 5% to 10% of thecomposition; or from 10% to 15% of the composition; or from 15% to 20%of the composition; or from 20% to 25% of the composition; or from 25%to 30% of the composition; or from 30% to 35% of the composition; orfrom 35% to 40% of the composition; or from 40% to 45% of thecomposition; or from 45% to 50% of the composition; or from 50% to 55%of the composition; or from 55% to 60% of the composition; or from 60%to 65% of the composition; or from 65% to 70% of the composition; orfrom 70% to 75% of the composition; or from 75% to 80% of thecomposition; or from 80% to 85% of the composition; or from 85% to 90%of the composition; or from 90% to 95% of the composition; or from 95%to 99% of the composition; or from 99% to 99.5% of the composition; orfrom 99.5% to 99.9% of the composition; or more than 99.9% of thecomposition. The HCFO-1233zd content may also vary within several of theabove ranges: for example, from 50% to 55% and from 55% to 60%, i.e.from 50% to 60%, etc.

The composition of the invention can be used in a heat transfer process.

The heat transfer process according to the invention is based on the useof a facility comprising a vapor compression system which contains thecomposition of the invention as heat-transfer fluid. The heat transferprocess may be a process for heating or cooling a fluid or a body.

The composition of the invention may also be used in a process forproducing mechanical working or electricity, in particular in accordancewith a Rankine cycle.

For the heating and cooling applications, the vapor compression systemcomprises at least one evaporator, one compressor, one condenser and oneexpansion valve, and also lines for transporting heat-transfer fluidbetween these components. The evaporator and the condenser comprise aheat exchanger making it possible to exchange heat between theheat-transfer fluid and another fluid or body.

By way of compressor, use may in particular be made of a centrifugalcompressor having one or more stages or of a centrifugalmini-compressor. Rotary compressors, spiral compressors, reciprocatingcompressors or screw compressors may also be used. The compressor may bedriven by an electric motor or by a gas turbine (for example fed by theexhaust gases of a vehicle, for mobile applications) or by gearing.

The vapor compression system then operates according to a conventionalvapor compression cycle. The cycle comprises the change of state of theheat-transfer fluid from a liquid phase (or liquid/vapor phase state) toa vapor phase at a relatively low pressure, then the compression of thefluid in the vapor phase up to a relatively high pressure, the change ofstate (condensation) of the heat-transfer fluid from the vapor phase tothe liquid phase at a relatively high pressure, and the reduction of thepressure so as to recommence the cycle.

The facility may also optionally comprise at least one circuit ofheat-transfer fluid used to transmit the heat (with or without change ofstate) between the heat-transfer fluid circuit and the fluid or body tobe heated or cooled.

The facility may also optionally comprise two (or more) vaporcompression systems, containing identical or distinct heat-transferfluids. For example, the vapor compression systems may be coupled to oneanother.

The cooling processes and facilities according to the invention compriseprocesses and facilities for air-conditioning (with mobile facilities,for example in vehicles, or stationary facilities), for refrigeration(with mobile facilities for example in containers, or stationaryfacilities) and for freezing or for cryogenics.

The heating facilities according to the invention comprise heat pumps.

For the applications for producing mechanical working or electricity,the facility is a thermal engine, which comprises at least oneevaporator, one turbine, one condenser and one pump, and also lines fortransporting heat-transfer fluid between these components. The facilitycan then operate according to a Rankine cycle.

It is possible to use any type of heat exchanger for the implementationof the heat-transfer fluids according to the invention, and inparticular concurrent heat exchangers, or, preferably, countercurrentheat exchangers.

In particular, the evaporator used in the context of the invention maybe a superheating evaporator or a flooded evaporator. In a superheatingevaporator, all of the heat-transfer fluid is evaporated at theevaporator outlet, and the vapor phase is superheated.

In a flooded evaporator, the heat-transfer fluid in liquid form does notcompletely evaporate. A flooded evaporator comprises a liquidphase/vapor phase separator.

The invention is particularly of use when such an evaporator is used.This is because the prior art stabilizers with a high boiling point areineffective when such an evaporator is used, since they concentrate inthe evaporator and do not migrate with the heat-transfer fluid to thecondenser.

The invention is also particularly of use when a high temperature existsat at least one point of the fluid circuit, and more particularly atemperature greater than or equal to 100° C., or greater than or equalto 110° C., or greater than or equal to 120° C., or greater than orequal to 130° C., or greater than or equal to 140° C., or greater thanor equal to 150° C., or greater than or equal to 160° C., or greaterthan or equal to 170° C., or greater than or equal to 180° C., orgreater than or equal to 190° C., or greater than or equal to 200° C.This is because it is under these conditions that HCFO-1233zdE is mostlikely to be converted into HCFO-1233zdZ.

In particular, in air-conditioning equipment, the general operatingtemperature is less than 100° C.; however, hot points at the compressoroutlet may reach temperatures greater than 100° C., affecting theheat-transfer fluid over the course of a small proportion of itscomplete circulation time (for example less than 1%).

In heat pumps, the condensation temperature may reach approximately 140°C. In this case, the heat-transfer fluid may be at a temperature ofapproximately 140° C. over the course of a large proportion of itscomplete circulation time (for example approximately 50%). Furthermore,hot points between 150 and 200° C. may also be noted at the compressoroutlet. The impact of a long residence time at temperatures greater than100° C. and the existence of points at temperatures which may be in theregion of 200° C. therefore require a stabilizer.

Likewise preferably, in the facility according to the invention, thetemperature of the composition used as heat-transfer fluid remainsgreater than the solidification temperature of the stabilizing compound,in order to prevent any deposit of solid material in the circuit.

The composition according to the invention may also be of use as ablowing agent, a propellant (for example for an aerosol), a cleaningagent or solvent, or a dielectric gas, in addition to its use as aheat-transfer fluid.

As a propellant, the composition according to the invention may be usedalone or in combination with known propellants. The propellantcomprises, preferably consists of, a composition according to theinvention. The active substance that must be propelled can be mixed withthe propellant and inert compounds, solvents or other additives, so asto form a composition to be propelled. Preferably, the composition to bepropelled is an aerosol.

As a blowing agent, the composition according to the invention may beincluded in a blowing composition, which preferably comprises one ormore other compounds capable of reacting and of forming a foam orcellular structure under appropriate conditions, as is known to thoseskilled in the art.

In particular, the invention provides a process for preparing anexpanded thermoplastic product comprising, first, the preparation of apolymeric blowing composition. Typically, the polymeric blowingcomposition is prepared by plasticizing a polymer resin and by mixing inthe compounds of a blowing agent composition at an initial pressure. Theplasticizing of the polymer resin can be carried out under the effect ofheat, by heating the polymer resin in order to soften it sufficiently tomix in a blowing agent composition. Generally, the plasticizingtemperature is close to the glass transition temperature or to themelting point for the crystalline polymers.

Other uses of the composition according to the invention comprise usesas a solvent, cleaning agent or the like. Mention may, for example, bemade of vapor degreasing, precision cleaning, the cleaning of electroniccircuits, dry cleaning, abrasive cleaning, solvents for the depositionof lubricants and release agents, and other solvent or surfacetreatments.

EXAMPLES

The following examples illustrate the invention without limiting it.

Example 1 (Comparative) Instability of HCFO-1233zdE in the Absence ofStabilizer

The tests for thermal stability of HCFO-1233zdE are carried outaccording to the standard ASHRAE 97-2007 entitled “Sealed glass tubemethod to test the chemical stability of materials for use withinrefrigerant systems”.

The compositions are determined by gas chromatography on a CP-sil8-CBcolumn.

A first series of tests is carried out at 150° C. for times of between10 minutes and 14 days. The results show a slight formation of theHFO-1233zdZ isomer, up to a content of 0.14% being reached at 14 days.

A second series of tests is carried out at 200° C. for a time of 24hours. The results show a slight formation of the HCFO-1233zdZ isomer upto a content of approximately 1% being reached.

Finally, a third series of tests is also carried out at 250° C. for atime of 24 hours. The results show a formation of the HCFO-1233zdZisomer of between 6% and 9%.

Example 2 (Invention) Stabilization of HCFO-1233zdE

Thermal stability tests similar to those of example 1 are carried out,while adding 0.5% of stabilizer to the HCFO-1233zdE (weight contentrelative to the sum of the stabilizer and of the HCFO-1233zdE). Thestabilizers tested are 2-methylbut-2-ene (2m2b) and 3-methylbut-1-ene(3m1b).

A first series of tests is carried out at 150° C. for a time of 14 days.The tests with 3m1b show a formation of the HCFO-1233zdZ isomer of about0.08% at the end of the period. In the tests with 2m2b, no HFO-1233zd-Zformation is measured.

A second series of tests is carried out at 200° C. for a time of 24hours. The tests with 3m1b show a slight formation of the HFO-1233zdZisomer of about 0.3%, and those with 2m2b show an HCFO-1233zdZ formationof about 0.07% at the end of this period.

The following table summarizes the stabilization effect observed:

HCFO-1233zdE HCFO-1233zdE + HCFO-1233zdE + alone 3m1b 2m2b 14 days at0.14% of 0.08% of HCFO-1233zdZ 150° C. HCFO-1233zdZ HCFO-1233zdZundetectable 24 hours at 1% of 0.3% of 0.07% of 200° C. HCFO-1233zdZHCFO-1233zdZ HCFO-1233zdZ

EMBODIMENTS

-   1. The use of a C₃ to C₆ alkene compound comprising a sole double    bond, for limiting or preventing the isomerization of    trans-1-chloro-3,3,3-trifluoropropene to    cis-1-chloro-3,3,3-trifluoropropene.-   2. The use as in embodiment 1, wherein the alkene compound is a    butene or a pentene.-   3. The use as in embodiment 1 or 2, wherein the alkene compound has:    -   a boiling point less than or equal to 100° C., preferably less        than or equal to 75° C., and more particularly preferably less        than or equal to 50° C.; and/or    -   a solidification temperature less than or equal to 0° C.,        preferably less than or equal to −25° C., and more particularly        preferably less than or equal to −50° C.-   4. The use as in embodiment 1, wherein the alkene compound is    2-methylbut-2-ene.-   5. The use as in embodiment 1, wherein the alkene compound is    3-methylbut-1-ene.-   6. A composition comprising 1-chloro-3,3,3-trifluoropropene and a C₃    to C₆ alkene compound comprising a sole double bond.-   7. The composition as in embodiment 6, wherein the alkene compound    is a butene or a pentene.-   8. The composition as in embodiment 6 or 7, wherein the alkene    compound has:    -   a boiling point less than or equal to 100° C., preferably less        than or equal to 75° C., and more particularly preferably less        than or equal to 50° C.; and/or    -   a solidification temperature less than or equal to 0° C.,        preferably less than or equal to −25° C., and more particularly        preferably less than or equal to −50° C.-   9. The composition as in embodiment 6, wherein the alkene compound    is 2-methylbut-2-ene.-   10. The composition as in embodiment 6, wherein the alkene compound    is 3-methylbut-1-ene.-   11. The composition as in one of embodiments 6 to 10, comprising    from 0.01% to 5%, preferably from 0.1% to 2% and more particularly    from 0.2% to 1%, by weight, of alkene compound.-   12. The composition as in one of embodiments 6 to 11, wherein the    1-chloro-3,3,3-trifluoropropene is in trans form in a weight    proportion greater than or equal to 90%, preferably greater than or    equal to 95%, more particularly preferably greater than or equal to    98%, even more particularly preferably greater than or equal to 99%,    and ideally greater than or equal to 99.5%, or even greater than    99.9%.-   13. The composition as in one of embodiments 6 to 12, also    comprising one or more heat-transfer compounds other than    1-chloro-3,3,3-trifluoropropene and/or one or more additives chosen    from stabilizers other than the alkene compound, lubricants,    surfactants, tracers, fluorescent agents, odorous agents,    solubilizing agents, and mixtures thereof.-   14. The use of a composition as in one of embodiments 6 to 13 as a    heat-transfer fluid in a vapor compression system.-   15. The use as in embodiment 14, wherein the vapor compression    system is:    -   an air-conditioning system; or    -   a refrigeration system; or    -   a freezing system; or    -   a heat pump system.-   16. The use of a composition as in one of embodiments 6 to 13 as a    heat-transfer fluid in a thermal engine.-   17. The use as in one of embodiments 14 to 16, wherein the    heat-transfer fluid is at a temperature greater than or equal to    100° C., preferably greater than or equal to 140° C., more    particularly preferably greater than or equal to 180° C., for at    least one fraction of the duration of its use.-   18. The use as in one of embodiments 14 to 17, wherein the    heat-transfer fluid is evaporated in a flooded evaporator.-   19. A heat transfer facility comprising a circuit containing a    composition as in one of embodiments 6 to 13 as a heat-transfer    fluid.-   20. The facility as in embodiment 19, chosen from mobile or    stationary facilities for heating via a heat pump, for    air-conditioning, for refrigeration or for freezing and thermal    engines.-   21. The facility as in embodiment 19 or 20, comprising a flooded    evaporator.-   22. A process for heating or cooling a fluid or a body by means of a    vapor compression system containing a heat-transfer fluid, said    process comprising successively the evaporation of the heat-transfer    fluid, the compression of the heat-transfer fluid, the condensation    of the heat-transfer fluid and the expansion of the heat-transfer    fluid, wherein the heat-transfer fluid is a composition as in one of    embodiments 6 to 13.-   23. A process for producing electricity by means of a thermal    engine, said process comprising successively the evaporation of the    heat-transfer fluid, the expansion of the heat-transfer fluid in a    turbine which makes it possible to generate electricity, the    condensation of the heat-transfer fluid and the compression of the    heat-transfer fluid, wherein the heat-transfer fluid is a    composition as in one of embodiments 6 to 13.

1. The use of a C₃ to C₆ alkene compound comprising a sole double bond,for limiting or preventing the isomerization oftrans-1-chloro-3,3,3-trifluoropropene tocis-1-chloro-3,3,3-trifluoropropene.